[IAUC] IAUC 9096: C/2009 W2; 169P [25139-2010/01-R1]

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                                                  Circular No. 9096
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET C/2009 W2 (BOATTINI)
     A. Boattini reports his discovery of a comet (discovery
observation tabulated below) on CCD images taken with the 0.68-m
Schmidt telescope in the course of the Catalina Sky Survey; he
notes a moderately condensed coma about 7" wide, with no tail
visible.  R. E. Hill reports that four co-added 60-s CCD images
taken in 2" seeing with the Mt. Lemmon 1.5-m reflector on Nov. 23.5
UT show a bright nuclear condensation with a small (1"-2") coma and
a short, broad tail 6"-7" long in p.a. about 80 deg; his similar
exposures on Nov. 24.44-24.46 show a 4" x 5" nuclear condensation
that is elongated east-west with a 1" coma surrounding, and a broad,
diffuse 30" tail in p.a. 90 deg.  After posting on the Minor Planet
Center's 'NEOCP' webpage, W. H. Ryan writes that CCD images taken
by E. V. Ryan and himself with the Magdalena Ridge Observatory
2.4-m f/8.9 reflector on Nov. 24.5 show a tail in p.a. about 90 deg.

     2009 UT             R.A. (2000) Decl.       Mag.   Observer
     Nov. 23.47597    6 21 30.50   +39 58 41.9   19.5   Boattini

The available astrometry (including observations by Boattini on
Nov. 21), the following preliminary parabolic orbital elements, and
an ephemeris appear on MPEC 2009-W103.

     T = 2010 Mar. 23.937 TT          Peri. = 118.066
                                      Node  = 199.323   2000.0
     q = 6.95031 AU                   Incl. = 164.512


COMET 169P/NEAT
     B. G. Marsden, Smithsonian Astrophysical Observatory, has
identified a comet found in STEREO spacecraft images with comet
169P.  K. Battams, Naval Research Laboratory, reports that the
comet appears very clearly (marginally diffuse with no tail) at
apparent mag about 9-10 on Nov. 12.9 UT in HI-1B images (limiting
mag about 13.5), when it was only about 4.5 deg from the sun (r =
0.69 AU, Delta = 0.88 AU, and 0.38 AU from STEREO), so that forward
scattering is a likely explanation for 169P's being well above its
observed brightness from ground-based observations (cf. MPEC
2009-W102).  Over the next few days, 169P moved to increasing
elongations, with its brightness falling gradually; by Nov. 21
(elongation 18 deg), STEREO images show the comet to be noticeably
smaller and fainter (mag perhaps 11-12).

                      (C) Copyright 2009 CBAT
2009 November 24               (9096)            Daniel W. E. Green